ANALYSIS OF CONSERVED AMINO ACID SEQUENCE MOTIFS IN NTPASES

不同NTP利用组中的保守氨基酸序列基序 利用计算机序列分析的方法对酶进行了研究 未探索蛋白质的NTPase活性预测结束，设计 序列数据库和数据库中NTPase的识别方案 生成这种类型的酶的基于序列的分类。 NTPase的特征是定义良好的保守基序 与底物结合和水解有关。氨基酸序列 在数据库中搜索所谓的A主题，它涉及到 对磷酸盐结合和由此产生的一组蛋白质进行了详细的探索 关于它们与其他蛋白质的相似性，以及可用的 有关NTPase活动的数据。三个不同的蛋白质家族带来了 结合A基序的经典形式和变异形式的NTPase是 特色化的。在E.coliDNAC中检测到一个修饰的NTP结合基序 蛋白质，结果表明该蛋白与Dna A有较远的亲缘关系 导致对DNA复制进化的影响 机械设备。确定了一个与DNAA相关的推定的ATPase 在一种古细菌病毒中。解旋酶活性被预测为几个 功能未知的蛋白质。出乎意料的是，解旋酶基序 在大肠杆菌中发现了SecA蛋白，这导致了一种假设，即该蛋白可能 有第二个活动，RNA双链解链，这可能对 翻译的自动调节。以前的小鼠蛋白MOV10 被认为是一个GTP酶，被证明与酵母解旋酶有关。MOV10 似乎是来自高等真核生物的第一个解旋酶，属于 所谓的超家族I.A蛋白(一种所谓的转录因子) 在数据库搜索中被发现，似乎只包含两个 解旋酶典型的七个保守基序，可以被认为是 在单独的蛋白质中分离的解旋酶结构域。关于划定的工作 序列模式将用作不同 解旋酶家族正在研究中。另一个正在进行的发展是 尝试将A基序概括为包括其他类型的NTP结合 以及其他小分子的结合位点，例如 S-腺苷蛋氨酸在甲基转移酶中的作用。 该项目的意义在于对NTPase活性的预测 对于许多未知功能的蛋白质，Allowed的特征 NTP结合基序的偏差，识别模式的推导 不同组的NTPase，并以序列为基础的发展 一大类酵素的分类。 语法=Z01LM00036 大分子蛋白质氨基酸序列的计算机辅助比较 DNA病毒之间以及与相关细胞蛋白的相互作用 执行，重点是可能特定影响的蛋白质 病毒的毒性。 大型DNA病毒的大量基因序列目前 包括一个完整的痘病毒基因组和几个疱疹病毒 基因组。由这些基因编码的大部分蛋白质的功能 病毒并不为人所知。特别令人感兴趣的是不是 在组织培养中对病毒生长是必不可少的，但会影响病毒 致命性。描述了一个痘病毒蛋白家族，它包含两个 明显不同的结构域，类似于明显无关的细胞蛋白。这个 N-末端结构域与几个相似位置的结构域相关 转录因子，C-末端结构域类似于小鼠 胎盘特异蛋白MIPP。后一个域由一组 四五次不完美的重复。我们的分析显示， 痘病毒中这一蛋白质家族的成员，提示存在一种复合体 可能涉及复制和缺失的进化途径。 预测了几种病毒NTP利用酶的功能， 包括两个痘病毒解旋酶和一个可能是 参与了病毒的成熟。在鸡痘病毒中发现了一种蛋白质 这与哺乳动物的胞苷酸激酶有关，被认为拥有 同样的酶活性。病毒和细胞的初步发展史 产生了胸腺嘧啶核苷和胸苷酸激酶，并提出了一个假设 开发出编码核苷酸代谢酶的基因可能是 由不同的病毒通过与 各自的细胞基因。锌指图案的一个特定版本是 在鼠痘病毒基因编码的蛋白质中鉴定，该病毒已被 在病毒疾病实验室进行了测序，并被证明是 使病毒对其自然宿主具有毒力是必不可少的。这个 对各自家族的锌指蛋白进行了比较分析 正在进行中。

Conserved amino acid sequence motifs in different groups of NTP-utilizing enzymes were studied using computer methods of sequence analysis to the end of predicting NTPase activity of unexplored proteins, designing schemes for identification of NTPases in sequence databases and generating a sequence-based classification of this type of enzymes. NTPases are characterized by well-defined conserved motifs that are implicated in substrate binding and hydrolysis. Amino acid sequence databases were searched for the so-called A motif that is involved in phosphate binding and the resulting set of proteins was explored in detail with respect to their similarities with other proteins, and the available data on NTPase activity. Three distinct protein families that bring together NTPases with classical and deviant forms of the A motif were characterized. A modified NTP-binding motif was detected in E.coli DnaC protein and it was shown that this protein is distantly related to DnaA leading to implications for the evolution of the DNA replication machinery. A putative ATPase that is also related to DnaA was identified in an archaebacterial virus. Helicase activity was predicted for several protein whose functions were unknown. Unexpectedly, helicase motifs were found in E.coli protein SecA leading to a hypothesis that this protein may have a second activity, RNA duplex unwinding, that might be important for autoregulation of translation. Murine protein MOV10 that was previously proposed to be a GTPase was shown to be related to yeast helicases. MOV10 appears to be the first helicase from a higher eukaryote that belongs to the so-called superfamily I. A protein (a purported transcription factor) was revealed upon database search that appeared to encompass only two of the seven conserved motifs typical of helicases and may be considered a helicase domain isolated in a separate protein. Work on delineation of sequence patterns that will serve as unique identifiers of different families of helicases is in progress. Another ongoing development is an attempt to generalize the A motif to include other types of NTP-binding sites and also binding sites for other small molecules, e.g. for S-adenosylmethionine in methyltransferases. The significance of the project is in the prediction of NTPase activity for many proteins with unknown functions, characterization of allowed deviations in NTP-binding motifs, derivation of identifying patterns for different groups of NTPases, and development of a sequence-based classification for a vast enzyme class. GRAMT=Z01LM00036 Computer-assisted comparisons of amino acid sequences of proteins of large DNA viruses with each other and with related cellular proteins were performed, with the emphasis on proteins that may specifically influence virus virulence. Vast collections of gene sequences of large DNA viruses are currently available, including one complete poxvirus genome and several herpesvirus genomes. The functions of a large fraction of proteins encoded by these viruses are not understood. Of particular interest are genes that are not essential for virus growth in tissue culture but influence virus virulence. A family of poxvirus proteins was described that contain two distinct domains similar to apparently unrelated cellular proteins. The N-terminal domain is related to similarly located domains of several transcription factors, and the C-terminal domain resembles a murine placental-specific protein MIPP. The latter domain consists of an array of four or five imperfect repeats. Our analysis revealed also truncated members of this protein family in poxviruses, suggesting a complex evolutionary pathway that might have involved duplications and deletions. Functions of several viral NTP-utilizing enzymes were predicted, including two poxvirus helicases and a putative NTPase that may be involved in virus maturation. A protein was identified in fowlpox virus that is related to mammalian cytidylate kinase and is proposed to possess the same enzymatic activity. A tentative phylogeny of viral and cellular thymidine and thymidylate kinases was generated and a hypothesis was developed that genes coding for enzymes of nucleotide metabolism could be acquired independently by different viruses via recombination with the respective cellular genes. A specific version of Zn finger motif was identified in a protein encoded by a gene of mousepox virus that has been sequenced in the Laboratory of Viral Diseases and has been shown to be essential for the virus to be virulent for its natural host. The comparative analysis of the Zn finger proteins of the respective family is in progress.